It also makes more sense for Safin to use a very conservative grip because he's so dang tall. The ball bounce is lower for him anyway, and so why not use a grip where the "strike zone" is right there.
The advantage is two-fold. First, it's practical since he doesn't want to claw down for low shots. Second, it means that his ideal strike height is much more variable than, say, an Agassi or Blake -- so he can crush these heavy topspin shots that your 6"1 guys can't.
But because it's more conservative, it means he's also playing with a lower safety net. More UEs and if his opponent is mixing up pace and junk and if he's not "feeling it", well he'll have a Safin meltdown. And you see that pattern with Blake and even early Agassi too. Unique to Safin, though, his height means he probably can't play any other way or effectively with a more extreme grip. Just too tall.